Repeated-action single-impact hammer

ABSTRACT

Repeated-action single-impact hammer having a cylinder that receives a reciprocating piston driven for translatory motion to deliver impacts upon rivets being headed. The free end of the cylinder carries a mechanism for centering the cylinder in respect of the stem of the rivet.

United States Patent Kushnarenko et al.

1 REPEATED-ACTION SINGLE-IMPACT HAMMER [76] Inventors: Sergei Grigorievich Kushnarenko,

ulitsa Chkalova l3, kv. 7; Vadim Grigorievich Kononenko, ulitsa Chkalova 15, kv.l2;'Vyacheslav Viktorovich Kollerov, ulitsa Gagarina, 38', kv. 60; Anatoly Sergeevich Morgolenko, ulitsa Chkalova, l5; Vladimir Mikhailovich Alimochkin, ulitsa Lermontovskaya, 26, kv. 4; Albert Ivanovich Orekhov, poselok Budy, ulitsa Oktyabrskaya, 113, all of Kharkov; Jury Mikhailovich t Komendantov, ulitsa Tallinskaya, 23, kv. 14, Leningrad; Lev Petrovich Vasilchenko, ulitsa Vododarskogo, 57a, kv. 10, Kharkov; Nikolai Mikhailovich Parkhomenko, ulitsa Otakara Yarosha, 23, kv. 4, Kharkov; Nikolai Nikolaevich Anistar0v,ulitsa Pomerovskaya, 4, kv. l, Kharkov, all of U.S.S.R.

[22] Filed: May 1, 1973 [21] Appl. No.: 356,195

[ 1 Jan. 7, 1975' [52] US. Cl. 72/430, 29/421 E [51] Int. Cl B2lj 15/18 [58] Field of Search 72/430, 391; 29/421 E, 29/200 E [56] References Cited UNITED STATES PATENTS 2,132,148 10/1938 Davis 72/430 3,543,560 l/1970 Harris 72/391 3,559,449 2/1971 Steinmetz 72/430 Primary ExaminerCharles W. Lanham,

' Assistant ExaminerGene P. Crosby Attorney, Agent, or Firm-Waters, Roditi, Schwartz &

Nissen [57] ABSTRACT Repeated-action single-impact hammer having a cylinder that receives a reciprocating piston driven for translatory motion to deliver impacts upon rivets being headed. The free end of the cylinder carries a mechanism for centering the cylinder in respect of the stern of the rivet. r

3 Claims, 5 Drawing Figures PATENTEDJA" H975 3,858,430

SHEET 20F 2 The invention relates to riveting equipment and, more particularly, it relates to hand-operated repeatedaction single-impact hammers.

A hammer constructed in accordance with the present invention is particularly adapted for closing up or heading rivets of a large diameter, made either of common grades of metals and alloys, or ofdeformationresistant metals and alloys.

.- driven by the expanding gunpowder gases in a translatory motion toward a rivet, to upon.

The housings ofthe known hammers further receive a trigger action with a firing pin adapted to fire the explosivecharge.

The abovespecified known hammers, although offering easy handling and wire operational facilities, since they are operable without any external energy sources, are, nevertheless not free from a serious drawback arising from the fact that they do not ensure reliable centering of the hammer in respect of a rivet, which affects the quality of riveting and might even lead to defective riveting. f

It is an object of the present invention to provide a hammer which improves the quality of heading rivets.

With this object in view, there is herein disclosed a repeated-action single-impact riveting or heading hamrner including-a housing wherein there is mounted a cylinder receiving thereinside a reciprocating piston adapted to deliver an impact upon a rivet, in which deliver an impact therehammer, in accordance with the present invention,,

there is further included a mechanism effecting centering of said cylinder in respect of a rivet, said mechanism being mounted on the end of said cylinder, adjoining the rivet, and'being movable radially into a contact with the stem of the rivet and back into the initial position thereof, the opposite end of said cylinder carrying radially resilient means for retaining said piston in the initial position thereof. I i

It is recommended that said mechanism for centering said cylinder in respect of the rivet includes two coaxially arranged sleeves of which one is rigidly fixed on the respective end of said cylinder, and the other one is rotatable in respect of said first sleeve, and a plurality of pivotable levers of which the pivot axes are uniformlyspaced about the end face of the sleeve which is fixed on said cylinder, and extend axially of cylinder, both said sleeves having cut therein radial grooves accommodating the arms of said levers.

The mechanism for centering the cylinder inrespect of the rivet is structurally simple and dependable in operation.

It is further expedient that said means for retaining said piston in the initial, or cocked position thereof includes a plurality of pins extending through openinings provided in said cylinder, said pins being spring-biased in the radial direction and bearing upon an annular groove cut in the periphery of said piston.

With the last-mentioned means being provided in this structure, the piston is reliably retained in the initial pothe invention;

2. sition thereof, and it becomes possible to attain a high piston impact speed upon the rivet, since acceleration of the piston commences only when the pressure is sufficiently high to overcome the resistance of the abovementionedspring bias.

The repeated-action single-imipact hammer con-' structed in accordance with the present invention ensures high quality heading of rivets since it features centering of the' cylinder in respect of the hammer and a high impact speed delivered by the piston upon the rivet.

The present invention will be further described in connection with an exemplary embodiment thereof, reference being had to the accompanying set of drawings, wherein:

FIG. 1 is a general partly broken away side view of a repeated-action single-impact hammer embodying FIG. 2 is a sectional view taken along line ll-Il of FIG. 1;

FIG. 3 is an enlarged axial view of the portion A of FIG. 1; i

FIG. 4 is a sectional view taken alongline IV-IV of FIG. 3, with the levers in theirinitial position; and

FIG. Sshows the same as FIG. 4, with the levers engaging a'rivet.

Referring now in particular to theappended drawings, the inventive repeated-action single-impact hammer comprises a housing 1 (FIG. 1) made up of two parts 2 and 3 threadedly secured to each other. The part 3 of the housing 1 has made therein a cavity 4 for accommodating therein acartridge: 5 with a gunpowder charge and a primer. The same part 3 of the housing 1 carries a handle 6 with a trigger action 7. A firing pin 8 of'thetrigger action 7 is positioned to strike the primer of the cartridge 5.

The part 2 of the housing 1 has mounted therein a cylinder 9 having an internal annular shoulder 10. The cylinder receives a reciprocating piston 11 having'a stepped-diameter shape.

Owing to this structure of the cylinder 9 and of the piston 11, the latter is retained in the cylinder 9 after it has completed its working stroke: under the action of the expanding gunpowder gases.

When the piston 11 is in an initialor cocked position, its end face closes off the cavity, in which position it is retained by a device 12. This device includes a plurality of pins 13 extending through respective radial openings in the cylinder 9, and'an annular spring 14 which biases the pins l3 into engagement with an annular groove 15 provided in the periphery of the piston 11.

The cylinder 9 is connected to the housing 1 through an elastic gasket 16 which absorbs the excessive energy of the working stroke.

The free end of the cylinder 9 carries a mechanism for centering the cylinder in respect of a stemmed rivet 17 to be headed. The mechanism includes a pair of coaxially arranged sleeves 18 and 19 and three pivoted levers 20. The sleeve 18 is rigidly fixed to the cylinder 9 and is prevented by a key 21 from rotation relative to the former.

The other sleeve 19 which is received about the sleeve 18 and the cylinder 9 is rotatable in respect of the latter, this being ensured by the cylinder 9 and the sleeve l8 having cut therein annular grooves adapted to accommodate therein balls 22. The balls are introduced into the grooves through holes 23 in the sleeve 19, which are normally closed by plug closures 24.

The levers 20 are of a two-arm structure, their pivot axes 25 being positioned in the area of the junction of the arms. The pivot axes are uniformly spaced about the internal end surface of the sleeve 18 and extend axially of the cylinder 9.

The sleeves l8 and 19 have respective radial slots 26, 27 cut therein to accommodate the outwardly extending arms of the levers 20, the other arms of these levers being adapted to close upon the stem of the rivet 17, when the levers are pivoted accordingly.

To return the rotatable sleeve 19 into its initial position, there is provided a torsion spring 28 of which one end is secured to the sleeve 19, and the opposite end is secured to the housing 1. p

The herein disclosed repeated-action single-impact hammer operates as follows. A cartridge with the necessary gunpowder charge is introduced into the cavity 4 of the housing 1. The hammer is then brought to the rivet 17, the operator holding the hammer with his right hand and using his left hand to rotate the sleeve 19 clockwise, the sleeve being externally knurled to facilitate this rotation.

As the sleeve 19 is being thus rotated, it acts upon the outwardly extending arms of the levers 20 accommodated in the slots 26, 27, whereby the levers 20 are pivoted about their axes 25.

When thus pivoted, the levers 20 have their internal arms radially displaced and closing upon the stem of the rivet l7, clamping the latter therebetween, in which way the cylinder 9 is centered in respect of the axis of the rivet. Simultaneously, the hammer is pressed against the panels that are to be riveted together. Then the operator releases the sleeve 19, and the latter is rotated back into its initial position by the torsion spring 28, whereby the levers 20 are pivoted off the rivet 17. By being thus pivoted back about their respective axes 25, the levers 20 resume their initial position-in which they do not interfere with the working stroke of the piston 11.

Then the operator pulls the trigger of the action 7, and the firing pin 8 strikes the primer of the cartridge 5 The gunpowder charge is thus fired, and thegases produced by the explosion of the charge expand and act upon the piston 11. The latter starts its acceleration only after the pressure of the expanding gases has exceeded a predetermined value, depending on the bias of the spring 14.

The exhaust gases leave the hammer through ports 29 and 30 provided, respectively, in the cylinder 9 and in the housing 1. I

By the end of its acceleration the piston 11 moves at a sufficient speed (up to 140 m/sec) to'develop a kinetic energy capable of high-quality heading the rivet 17 with a single impact.

The piston 11 is retained within the cylinder 9, at first, by the resistance of the rivet 17 to its deformation, and then, when the deformation has been completed, by the piston being arrested by the internal annular shoulder 10 of the cylinder 9.

A special-design ramrod (not shown) is used to return the piston 11 into its initial position, whereafter the operating cycle can be repeated for heading a successive rivet.

What is claimed is:

l. A repeated-action single-impact hammer for heading stemmed rivets, comprising: a housing; a cylinder mounted in said housing; a piston received in said cylinder for translatory reciprocating motion so as to deliver an impact upon a rivet; means for driving said piston, positioned in said housing; a mechanism effecting centering of said cylinder with respect to the rivet, mounted on an end portion of said cylinder, adjoining in operation of heading the rivet, said mechanism being radially movable into contact with the stem or the rivet and back into the initial position thereof; and radially resilient means for retaining said piston in the initial position thereof, mounted on the other end portion of said cylinder, opposite'to said one end portion thereof.

2. The hammer as defined in claim 1, wherein said centering mechanism includes a pair of coaxially arranged sleeves of which one is rigidly fixed to said one end portion of the cylinder and the other sleeve is rotatable relative to said one sleeve, and a plurality of pivotable levers having their respective pivot axes uniformly spaced about the end face of said one sleeve which is fixed to the cylinder, and extending axially of said cylinder, said sleeves having appropriate-radial slots cut therein to accommodate arms of said levers.

3. The hammer as defined in claim 1, wherein said retaining means includes a plurality of pins extending ton. 

1. A repeated-action single-impact hammer for heading stemmed rivets, comprising: a housing; a cylinder mounted in said housing; a piston received in said cylinder for translatory reciprocating motion so as to deliver an impact upon a rivet; means for driving said piston, positioned in said housing; a mechanism effecting centering of said cylinder with respect to the rivet, mounted on an end portion of said cylinder, adjoining in operation of heading the rivet, said mechanism being radially movable into contact with the stem or the rivet and back into the initial position thereof; and radially resilient means for retaining said piston in the initial position thereof, mounted on the other end portion of said cylinder, opposite to Said one end portion thereof.
 2. The hammer as defined in claim 1, wherein said centering mechanism includes a pair of coaxially arranged sleeves of which one is rigidly fixed to said one end portion of the cylinder and the other sleeve is rotatable relative to said one sleeve, and a plurality of pivotable levers having their respective pivot axes uniformly spaced about the end face of said one sleeve which is fixed to the cylinder, and extending axially of said cylinder, said sleeves having appropriate radial slots cut therein to accommodate arms of said levers.
 3. The hammer as defined in claim 1, wherein said retaining means includes a plurality of pins extending through openings provided in said cylinder, said pins being spring-biased in a radial direction and bearing upon an annular groove cut in the periphery of said piston. 